Tag Archives: Varroa

Because of the nice weather in winter and spring the varroa populations have exploded. Winter treatment against varroa using oxalic acid is used during winter because that it is the only time that the colony is not expected to have any brood. A single treatment should impact all varroa as there should be no varroa protected inside caped brood cells.

But because of the mild weather this winter there is a good chance that the bees did have capped brood, most likely filled with varroa. And then there was the mild spring which gave the mites a head start in the bee season letting their population grow to new heights. That is why this year the varroa treatments here in western Europe are especially important. Varroa can be a major cause in colony death over winter. More so than lack of food or extreme cold.

The local apiarists organisation in the Netherlands has published an article on the explosive varroa population growth. A beekeeper counted 4 times the varroa he would count in an average year. You can view a translation of the article by following this next link (in all honesty the translation isn’t all that good, but kind of readable).

I’m not sure how the varroa population is going in my hives. I’ll check the mite drop after the 5 weeks of apiguard treatment tomorrow and update this post accordingly (if the weather allows, lot of rain here lately).

I’m using a, for me, new tool in my effort to combat varroa in my colonies, apiguard. You place a “serving” of apiguard on top of the top bars of the frames and leave it there for two weeks and repeat.

Worker bees climb into the Apiguard tray, remove the gel as a hive-cleaning behaviour and distribute it throughout the colony. The gel sticks to the bees’ body hairs and, as the bees move through the hive, particles are left throughout the hive. The worker eventually throws out the gel it is carrying, but the traces remain until they too are removed later.

The gel acts like a slow thymol release agent. Thymol is a naturally occurring substance that has proven to work as an anti varroa agent as well as being an antimicrobial and fungicidal substance. Seeing my earlier experience with formic acid, this perhaps is a good alternative. Although I forgot to place a bottom board in the hives to see the varroa drop, thus making it hard to compare it to the formic acid treatment. But perhaps I’ll see less varroa in December when I treat with oxalic acid because of this treatment.

You do need to be done with your honey harvest because the thymol will also dissolve into the honey giving it a distinctly unpleasant taste. You should also not feed the bees while giving this treatment because the bees will be to busy with storing the feed syrup to disperse the thymol gel.

Otherwise Sif and Artemis are looking good. Next on the todo list is judging the fitness of the colonies in the light of winter survival. Will need to asses their size and food supply to estimate how much feeding they will need.

Siting in front of my hive one day, the hive at my parents house, I saw a bee stumble out of the hive and drop onto the ground. On the ground the bee continued to crawl on. I was surprised and concerned. I gathered up the bee to get a better look at it. There was clearly something wrong with it’s wings. It didn’t try to fly and fell to the ground when falling off of my hand. I had recently read about deformed wing virus (DWV) and that it could be an indication of a Varroa destructor infection as an opportunistic pathogen. After reading some more I was quit sure this was DWV. The wings were clearly deformed, not as bad as you can find on the interwebs, but you’ll see if you click on the image on the left it’s bad enough.

It was right before the time I needed to treat the colony against varroa with formic acid so I was hoping that would take care of the problem. Other beekeepers I knew didn’t seem all that concerned so I reasoned that it wasn’t extraordinary. Still after my previous troubles, I wasn’t all that certain. Apparently the formic acid treatment was enough, I saw no more bees with DWV, the bees don’t last long after crawling out of the comb with this affliction so I guess no more bees with clear DWV were “born”.

Without Varroa the bees can handle DWV fine but Varroa makes them more susceptible to any disease. Varroa mites will often be carriers of DWV and in that way infect the bees. According to the Wikipedia article Varroa will serve as a kind of incubator for DWV and only colonies with a serious Varroa infestation suffer from it. I can only hope that the bees are relatively free of Varroa now and will make sure to treat them against Varroa next year so they stay or become healthy.

August is the time to treat the bees against Varroa infection. This mite, aptly named Varroa destructor, is one of the most serious enemies of the honey bee. It is a pest imported from the far east and has been spreading over Europe and the rest of the world for the last 40 years or so. Only Australia is free of this pest and I’m sure they hope to keep it that way.

Without treatment your colony will surely die. Most likely not of the Varroa mites them selfs but of secondary/opportunistic infections like deformed wing virus (DWV). In the Netherlands organizations, like bijen@WUR, researches bee health and are on the lookout for causes of bee disease and research and test treatment plans. So far there is no sure way to be rid of the Varroa, all we have so far are means to keep the Varroa at bay.

One of the treatments against Varroa is drenching your bees in formic acid vapor for about 14 days. The time to do this is after you have harvested the last of the honey so at the end of July or at the beginning of August. There are other treatments but this is article is about the treatment I performed.

You can perform this treatment in a number of ways, the one I employed, which I think is the easiest and cheapest one, is by placing a clean household cloth on top of a queen excluder on the top brood box, placing an empty honey super on top and soaking the cloth in a certain amount (30 ml per brood box) of formic acid (60%). You will leave this cloth with acid in the hive for 4-5 days and repeat the procedure twice to get a treatment totaling about 14 days, to get all the mites also in closed brood.

Liebig dispencer

Perhaps an easier way but one requiring buying some gear entails buying a Liebig dispenser shown in the image below. It requires a little less effort and uses 85% formic acid in stead of 60%, which is the concentration that is readily available and so doesn’t require diluting. The dispenser is not expensive, so I guess that will be the method I will be employing in the future. I am myself the best example why not having to dilute you formic acid is an advantage. Having worked in chemical/biological labs for in total well over a year, and having instructed young students in lab practices, I didn’t think to much of working with 85% formic acid. As I had bought 85% formic acid and needed 60% it needed to be diluted, no big deal I thought until the bottle of formic acid slipped out of my wet gloves fell and bumped on the bottom of the bath where I was doing the dilution and sprayed 85% formic acid in my face. I got it on my cheeks and on my throat and a droplet in my eye. After dosing my face under the tap for about a minute, while all the formic acid went down the drain, I opened the bathroom door which my wife was about to break down having heard the commotion. After a visit to the doctor I had to have a large band aid covering my eye for a day and had to drop antibiotic liquid in my eye for three days. The burn marks in my face and throat were gone in a little over a week. It didn’t really hurt but the acid did burn in my eye. There is no lasting damage but I was obviously mortified that I could have been so clumsy and careless.

I finally bought a new bottle and performed the dilution at a lab of a biologist friend, no drama what soever…and the procedure with the hives went down without a hitch. I could have done it easily in a sink, the bath was not the best choice. You just have to be careful, wear eye and hand protection and be organized. And if all else fails find a place that sells it at the right concentration for your method or use a method that uses the 85% concentration.

So the take home message is; don’t spill formic acid in your eye, it hurts and is a major bother.

Bees are an essential part of our ecology, not only are they responsible for the pollination of many of our food crops, some sources say that about a third of the human food crops require honey bee pollination. Although there obviously are more pollinating insects none are as productive or fastidious as the honey bee. But honey bees not only pollinate they also produce honey, propolis, wax and royal jelly.

Throughout the world we see a decline in honey bee populations as well as in the population of wild bees. Beekeepers will visit their hives one day and find some simply empty, a phenomenon termed colony collapse disorder (CCD). Or beekeepers will come to their hives after winter and find up to half the colonies died over the winter, although that can also be attributed to bad management.

The cause of honey bee population decline is a topic for hefty debate and scientific study. There are a number of possible culprits for the global decline of honey bees, like pesticides (specially the neonicotinoid variant); mite infections (mainly the Varroa destructor and to a lesser extent Acarapis); habitat destruction (see below); pathogens. Especially in the US the apicultural practices are also a cause with beekeepers driving their bees around in trucks carrying more than a few hundred hives. It is most likely a combination of these factors as none of these factors on its own seems serious enough to cause such devastation.

The green desert, that is what us beekeepers aptly name most farmland, especially farm land used for animal (mainly cow) farming. There is nothing for the bees or other insects in these meadows. Cattle farmers want to grow grass and only grass. Dandelions mixed in with your grass? Heresy! (bees like dandelions) Habitat destruction seems one cause that can be easily mended by adjusting the agricultural practices. Have borders to agricultural plots with wild flowers which would break up the green desert. This is also the main reason why these days bees tend to prosper in urban areas. Bees can find the things in gardens and public parks they can’t find in rural areas, food.

Okay this is slightly over the top

The question is can “we the people” do something about this? Yes! I guess you could buy a flowering plant seed mix specially designed for bees. Then go looking for some unused plots of land in you neighborhood and sow some of the seeds there. Perhaps a more constructive and longer lasting way would be to petition you local counsel to use any unused land specifically for growing wild flowers useful for bees. I’m sure your local beekeepers as well as any wild (solitary) bees and bumble bees will be very thankful. An other thing you could do, this time not specifically for honey bees, is buy or make a bee hotel. This way you would be supporting the local solitary bees even more. There are over 20000 species of bee most of them solitary, the honey bee (Apis mellifera) is just one species of bee.